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Comparing jsr166/src/main/java/util/ArrayDeque.java (file contents):
Revision 1.95 by jsr166, Sat Oct 29 19:10:27 2016 UTC vs.
Revision 1.109 by jsr166, Sat Nov 5 16:21:06 2016 UTC

#	Line 60 | Line 60 | import java.util.function.UnaryOperator;
60		public class ArrayDeque<E> extends AbstractCollection<E>
61		implements Deque<E>, Cloneable, Serializable
62		{
63	+	/*
64	+	* VMs excel at optimizing simple array loops where indices are
65	+	* incrementing or decrementing over a valid slice, e.g.
66	+	*
67	+	* for (int i = start; i < end; i++) ... elements[i]
68	+	*
69	+	* Because in a circular array, elements are in general stored in
70	+	* two disjoint such slices, we help the VM by writing unusual
71	+	* nested loops for all traversals over the elements.
72	+	*/
73	+
74		/**
75		* The array in which the elements of the deque are stored.
76		* We guarantee that all array cells not holding deque elements
#	Line 70 | Line 81 | public class ArrayDeque<E> extends Abstr
81		/**
82		* The index of the element at the head of the deque (which is the
83		* element that would be removed by remove() or pop()); or an
84	<	* arbitrary number 0 <= head < elements.length if the deque is empty.
84	>	* arbitrary number 0 <= head < elements.length equal to tail if
85	>	* the deque is empty.
86		*/
87		transient int head;
88
89	<	/** Number of elements in this collection. */
90	<	transient int size;
89	>	/**
90	>	* The index at which the next element would be added to the tail
91	>	* of the deque (via addLast(E), add(E), or push(E)).
92	>	*/
93	>	transient int tail;
94
95		/**
96		* The maximum size of array to allocate.
#	Line 92 | Line 107 | public class ArrayDeque<E> extends Abstr
107		*/
108		private void grow(int needed) {
109		// overflow-conscious code
95	–	// checkInvariants();
110		final int oldCapacity = elements.length;
111		int newCapacity;
112	<	// Double size if small; else grow by 50%
112	>	// Double capacity if small; else grow by 50%
113		int jump = (oldCapacity < 64) ? (oldCapacity + 2) : (oldCapacity >> 1);
114		if (jump < needed
115		|| (newCapacity = (oldCapacity + jump)) - MAX_ARRAY_SIZE > 0)
116		newCapacity = newCapacity(needed, jump);
117		elements = Arrays.copyOf(elements, newCapacity);
118	<	if (oldCapacity - head < size) {
118	>	// Exceptionally, here tail == head needs to be disambiguated
119	>	if (tail < head || (tail == head && elements[head] != null)) {
120		// wrap around; slide first leg forward to end of array
121		int newSpace = newCapacity - oldCapacity;
122		System.arraycopy(elements, head,
#	Line 136 | Line 151 | public class ArrayDeque<E> extends Abstr
151		* @since TBD
152		*/
153		/* public */ void ensureCapacity(int minCapacity) {
154	<	if (minCapacity > elements.length)
155	<	grow(minCapacity - elements.length);
154	>	int needed;
155	>	if ((needed = (minCapacity + 1 - elements.length)) > 0)
156	>	grow(needed);
157		// checkInvariants();
158		}
159
#	Line 147 | Line 163 | public class ArrayDeque<E> extends Abstr
163		* @since TBD
164		*/
165		/* public */ void trimToSize() {
166	<	if (size < elements.length) {
167	<	elements = toArray();
166	>	int size;
167	>	if ((size = size()) + 1 < elements.length) {
168	>	elements = toArray(new Object[size + 1]);
169		head = 0;
170	+	tail = size;
171		}
172		// checkInvariants();
173		}
#	Line 169 | Line 187 | public class ArrayDeque<E> extends Abstr
187		* @param numElements lower bound on initial capacity of the deque
188		*/
189		public ArrayDeque(int numElements) {
190	<	elements = new Object[numElements];
190	>	elements = new Object[Math.max(1, numElements + 1)];
191		}
192
193		/**
#	Line 183 | Line 201 | public class ArrayDeque<E> extends Abstr
201		* @throws NullPointerException if the specified collection is null
202		*/
203		public ArrayDeque(Collection<? extends E> c) {
204	<	Object[] es = c.toArray();
205	<	// defend against c.toArray (incorrectly) not returning Object[]
188	<	// (see e.g. https://bugs.openjdk.java.net/browse/JDK-6260652)
189	<	if (es.getClass() != Object[].class)
190	<	es = Arrays.copyOf(es, es.length, Object[].class);
191	<	for (Object obj : es)
192	<	Objects.requireNonNull(obj);
193	<	this.elements = es;
194	<	this.size = es.length;
204	>	elements = new Object[c.size() + 1];
205	>	addAll(c);
206		}
207
208		/**
#	Line 222 | Line 233 | public class ArrayDeque<E> extends Abstr
233		}
234
235		/**
236	<	* Returns the array index of the last element.
237	<	* May return invalid index -1 if there are no elements.
236	>	* Subtracts j from i, mod modulus.
237	>	* Index i must be logically ahead of j.
238	>	* Returns the "circular distance" from j to i.
239	>	* Precondition and postcondition: 0 <= i < modulus, 0 <= j < modulus.
240		*/
241	<	final int tail() {
242	<	return add(head, size - 1, elements.length);
241	>	static final int sub(int i, int j, int modulus) {
242	>	if ((i -= j) < 0) i += modulus;
243	>	return i;
244		}
245
246		/**
247		* Returns element at array index i.
248	+	* This is a slight abuse of generics, accepted by javac.
249		*/
250		@SuppressWarnings("unchecked")
251	<	private E elementAt(int i) {
252	<	return (E) elements[i];
251	>	static final <E> E elementAt(Object[] es, int i) {
252	>	return (E) es[i];
253		}
254
255		/**
256		* A version of elementAt that checks for null elements.
257		* This check doesn't catch all possible comodifications,
258	<	* but does catch ones that corrupt traversal.  It's a little
244	<	* surprising that javac allows this abuse of generics.
258	>	* but does catch ones that corrupt traversal.
259		*/
260	<	static final <E> E nonNullElementAt(Object[] elements, int i) {
261	<	@SuppressWarnings("unchecked") E e = (E) elements[i];
260	>	static final <E> E nonNullElementAt(Object[] es, int i) {
261	>	@SuppressWarnings("unchecked") E e = (E) es[i];
262		if (e == null)
263		throw new ConcurrentModificationException();
264		return e;
#	Line 261 | Line 275 | public class ArrayDeque<E> extends Abstr
275		* @throws NullPointerException if the specified element is null
276		*/
277		public void addFirst(E e) {
278	<	// checkInvariants();
279	<	Objects.requireNonNull(e);
280	<	Object[] es;
281	<	int capacity, h;
282	<	final int s;
269	<	if ((s = size) == (capacity = (es = elements).length)) {
278	>	if (e == null)
279	>	throw new NullPointerException();
280	>	final Object[] es = elements;
281	>	es[head = dec(head, es.length)] = e;
282	>	if (head == tail)
283		grow(1);
271	–	capacity = (es = elements).length;
272	–	}
273	–	if ((h = head - 1) < 0) h = capacity - 1;
274	–	es[head = h] = e;
275	–	size = s + 1;
284		// checkInvariants();
285		}
286
#	Line 285 | Line 293 | public class ArrayDeque<E> extends Abstr
293		* @throws NullPointerException if the specified element is null
294		*/
295		public void addLast(E e) {
296	<	// checkInvariants();
297	<	Objects.requireNonNull(e);
298	<	Object[] es;
299	<	int capacity;
300	<	final int s;
293	<	if ((s = size) == (capacity = (es = elements).length)) {
296	>	if (e == null)
297	>	throw new NullPointerException();
298	>	final Object[] es = elements;
299	>	es[tail] = e;
300	>	if (head == (tail = inc(tail, es.length)))
301		grow(1);
295	–	capacity = (es = elements).length;
296	–	}
297	–	es[add(head, s, capacity)] = e;
298	–	size = s + 1;
302		// checkInvariants();
303		}
304
#	Line 311 | Line 314 | public class ArrayDeque<E> extends Abstr
314		*         of its elements are null
315		*/
316		public boolean addAll(Collection<? extends E> c) {
317	<	final int s = size, needed = c.size() - (elements.length - s);
318	<	if (needed > 0)
317	>	final int s = size(), needed;
318	>	if ((needed = s + c.size() - elements.length + 1) > 0)
319		grow(needed);
320		c.forEach((e) -> addLast(e));
321		// checkInvariants();
322	<	return size > s;
322	>	return size() > s;
323		}
324
325		/**
#	Line 347 | Line 350 | public class ArrayDeque<E> extends Abstr
350		* @throws NoSuchElementException {@inheritDoc}
351		*/
352		public E removeFirst() {
350	–	// checkInvariants();
353		E e = pollFirst();
354		if (e == null)
355		throw new NoSuchElementException();
356	+	// checkInvariants();
357		return e;
358		}
359
#	Line 358 | Line 361 | public class ArrayDeque<E> extends Abstr
361		* @throws NoSuchElementException {@inheritDoc}
362		*/
363		public E removeLast() {
361	–	// checkInvariants();
364		E e = pollLast();
365		if (e == null)
366		throw new NoSuchElementException();
367	+	// checkInvariants();
368		return e;
369		}
370
371		public E pollFirst() {
372	+	final Object[] es;
373	+	final int h;
374	+	E e = elementAt(es = elements, h = head);
375	+	if (e != null) {
376	+	es[h] = null;
377	+	head = inc(h, es.length);
378	+	}
379		// checkInvariants();
370	–	int s, h;
371	–	if ((s = size) <= 0)
372	–	return null;
373	–	final Object[] elements = this.elements;
374	–	@SuppressWarnings("unchecked") E e = (E) elements[h = head];
375	–	elements[h] = null;
376	–	if (++h >= elements.length) h = 0;
377	–	head = h;
378	–	size = s - 1;
380		return e;
381		}
382
383		public E pollLast() {
384	+	final Object[] es;
385	+	final int t;
386	+	E e = elementAt(es = elements, t = dec(tail, es.length));
387	+	if (e != null)
388	+	es[tail = t] = null;
389		// checkInvariants();
384	–	final int s, tail;
385	–	if ((s = size) <= 0)
386	–	return null;
387	–	final Object[] elements = this.elements;
388	–	@SuppressWarnings("unchecked")
389	–	E e = (E) elements[tail = add(head, s - 1, elements.length)];
390	–	elements[tail] = null;
391	–	size = s - 1;
390		return e;
391		}
392
#	Line 396 | Line 394 | public class ArrayDeque<E> extends Abstr
394		* @throws NoSuchElementException {@inheritDoc}
395		*/
396		public E getFirst() {
397	+	E e = elementAt(elements, head);
398	+	if (e == null)
399	+	throw new NoSuchElementException();
400		// checkInvariants();
401	<	if (size <= 0) throw new NoSuchElementException();
401	<	return elementAt(head);
401	>	return e;
402		}
403
404		/**
405		* @throws NoSuchElementException {@inheritDoc}
406		*/
407	–	@SuppressWarnings("unchecked")
407		public E getLast() {
408	+	final Object[] es = elements;
409	+	E e = elementAt(es, dec(tail, es.length));
410	+	if (e == null)
411	+	throw new NoSuchElementException();
412		// checkInvariants();
413	<	final int s;
411	<	if ((s = size) <= 0) throw new NoSuchElementException();
412	<	final Object[] elements = this.elements;
413	<	return (E) elements[add(head, s - 1, elements.length)];
413	>	return e;
414		}
415
416		public E peekFirst() {
417		// checkInvariants();
418	<	return (size <= 0) ? null : elementAt(head);
418	>	return elementAt(elements, head);
419		}
420
421	–	@SuppressWarnings("unchecked")
421		public E peekLast() {
422		// checkInvariants();
423	<	final int s;
424	<	if ((s = size) <= 0) return null;
426	<	final Object[] elements = this.elements;
427	<	return (E) elements[add(head, s - 1, elements.length)];
423	>	final Object[] es;
424	>	return elementAt(es = elements, dec(tail, es.length));
425		}
426
427		/**
#	Line 441 | Line 438 | public class ArrayDeque<E> extends Abstr
438		*/
439		public boolean removeFirstOccurrence(Object o) {
440		if (o != null) {
441	<	final Object[] elements = this.elements;
442	<	final int capacity = elements.length;
443	<	int i, end, to, todo;
447	<	todo = (end = (i = head) + size)
448	<	- (to = (capacity - end >= 0) ? end : capacity);
449	<	for (;; to = todo, i = 0, todo = 0) {
441	>	final Object[] es = elements;
442	>	for (int i = head, end = tail, to = (i <= end) ? end : es.length;
443	>	; i = 0, to = end) {
444		for (; i < to; i++)
445	<	if (o.equals(elements[i])) {
445	>	if (o.equals(es[i])) {
446		delete(i);
447		return true;
448		}
449	<	if (todo == 0) break;
449	>	if (to == end) break;
450		}
451		}
452		return false;
#	Line 472 | Line 466 | public class ArrayDeque<E> extends Abstr
466		*/
467		public boolean removeLastOccurrence(Object o) {
468		if (o != null) {
469	<	final Object[] elements = this.elements;
470	<	final int capacity = elements.length;
471	<	int i, to, end, todo;
472	<	todo = (to = ((end = (i = tail()) - size) >= -1) ? end : -1) - end;
473	<	for (;; to = (i = capacity - 1) - todo, todo = 0) {
480	<	for (; i > to; i--)
481	<	if (o.equals(elements[i])) {
469	>	final Object[] es = elements;
470	>	for (int i = tail, end = head, to = (i >= end) ? end : 0;
471	>	; i = es.length, to = end) {
472	>	while (--i >= to)
473	>	if (o.equals(es[i])) {
474		delete(i);
475		return true;
476		}
477	<	if (todo == 0) break;
477	>	if (to == end) break;
478		}
479		}
480		return false;
#	Line 610 | Line 602 | public class ArrayDeque<E> extends Abstr
602		* <p>This method is called delete rather than remove to emphasize
603		* that its semantics differ from those of {@link List#remove(int)}.
604		*
605	<	* @return true if elements moved backwards
605	>	* @return true if elements near tail moved backwards
606		*/
607		boolean delete(int i) {
608		// checkInvariants();
609	<	final Object[] elements = this.elements;
610	<	final int capacity = elements.length;
609	>	final Object[] es = elements;
610	>	final int capacity = es.length;
611		final int h = head;
612	<	int front;              // number of elements before to-be-deleted elt
613	<	if ((front = i - h) < 0) front += capacity;
614	<	final int back = size - front - 1; // number of elements after
612	>	// number of elements before to-be-deleted elt
613	>	final int front = sub(i, h, capacity);
614	>	final int back = size() - front - 1; // number of elements after
615		if (front < back) {
616		// move front elements forwards
617		if (h <= i) {
618	<	System.arraycopy(elements, h, elements, h + 1, front);
618	>	System.arraycopy(es, h, es, h + 1, front);
619		} else { // Wrap around
620	<	System.arraycopy(elements, 0, elements, 1, i);
621	<	elements[0] = elements[capacity - 1];
622	<	System.arraycopy(elements, h, elements, h + 1, front - (i + 1));
620	>	System.arraycopy(es, 0, es, 1, i);
621	>	es[0] = es[capacity - 1];
622	>	System.arraycopy(es, h, es, h + 1, front - (i + 1));
623		}
624	<	elements[h] = null;
625	<	if ((head = (h + 1)) >= capacity) head = 0;
634	<	size--;
624	>	es[h] = null;
625	>	head = inc(h, capacity);
626		// checkInvariants();
627		return false;
628		} else {
629		// move back elements backwards
630	<	int tail = tail();
630	>	tail = dec(tail, capacity);
631		if (i <= tail) {
632	<	System.arraycopy(elements, i + 1, elements, i, back);
632	>	System.arraycopy(es, i + 1, es, i, back);
633		} else { // Wrap around
634		int firstLeg = capacity - (i + 1);
635	<	System.arraycopy(elements, i + 1, elements, i, firstLeg);
636	<	elements[capacity - 1] = elements[0];
637	<	System.arraycopy(elements, 1, elements, 0, back - firstLeg - 1);
635	>	System.arraycopy(es, i + 1, es, i, firstLeg);
636	>	es[capacity - 1] = es[0];
637	>	System.arraycopy(es, 1, es, 0, back - firstLeg - 1);
638		}
639	<	elements[tail] = null;
649	<	size--;
639	>	es[tail] = null;
640		// checkInvariants();
641		return true;
642		}
#	Line 660 | Line 650 | public class ArrayDeque<E> extends Abstr
650		* @return the number of elements in this deque
651		*/
652		public int size() {
653	<	return size;
653	>	return sub(tail, head, elements.length);
654		}
655
656		/**
#	Line 669 | Line 659 | public class ArrayDeque<E> extends Abstr
659		* @return {@code true} if this deque contains no elements
660		*/
661		public boolean isEmpty() {
662	<	return size == 0;
662	>	return head == tail;
663		}
664
665		/**
#	Line 693 | Line 683 | public class ArrayDeque<E> extends Abstr
683		int cursor;
684
685		/** Number of elements yet to be returned. */
686	<	int remaining = size;
686	>	int remaining = size();
687
688		/**
689		* Index of element returned by most recent call to next.
#	Line 710 | Line 700 | public class ArrayDeque<E> extends Abstr
700		public E next() {
701		if (remaining <= 0)
702		throw new NoSuchElementException();
703	<	final Object[] elements = ArrayDeque.this.elements;
704	<	E e = nonNullElementAt(elements, cursor);
703	>	final Object[] es = elements;
704	>	E e = nonNullElementAt(es, cursor);
705		lastRet = cursor;
706	<	if (++cursor >= elements.length) cursor = 0;
706	>	cursor = inc(cursor, es.length);
707		remaining--;
708		return e;
709		}
710
711		void postDelete(boolean leftShifted) {
712		if (leftShifted)
713	<	if (--cursor < 0) cursor = elements.length - 1;
713	>	cursor = dec(cursor, elements.length);
714		}
715
716		public final void remove() {
#	Line 731 | Line 721 | public class ArrayDeque<E> extends Abstr
721		}
722
723		public void forEachRemaining(Consumer<? super E> action) {
724	<	final int k;
725	<	if ((k = remaining) > 0) {
726	<	remaining = 0;
727	<	ArrayDeque.forEachRemaining(action, elements, cursor, k);
728	<	if ((lastRet = cursor + k - 1) >= elements.length)
729	<	lastRet -= elements.length;
724	>	Objects.requireNonNull(action);
725	>	int r;
726	>	if ((r = remaining) <= 0)
727	>	return;
728	>	remaining = 0;
729	>	final Object[] es = elements;
730	>	if (es[cursor] == null || sub(tail, cursor, es.length) != r)
731	>	throw new ConcurrentModificationException();
732	>	for (int i = cursor, end = tail, to = (i <= end) ? end : es.length;
733	>	; i = 0, to = end) {
734	>	for (; i < to; i++)
735	>	action.accept(elementAt(es, i));
736	>	if (to == end) {
737	>	if (end != tail)
738	>	throw new ConcurrentModificationException();
739	>	lastRet = dec(end, es.length);
740	>	break;
741	>	}
742		}
743		}
744		}
745
746		private class DescendingIterator extends DeqIterator {
747	<	DescendingIterator() { cursor = tail(); }
747	>	DescendingIterator() { cursor = dec(tail, elements.length); }
748
749		public final E next() {
750		if (remaining <= 0)
751		throw new NoSuchElementException();
752	<	final Object[] elements = ArrayDeque.this.elements;
753	<	E e = nonNullElementAt(elements, cursor);
752	>	final Object[] es = elements;
753	>	E e = nonNullElementAt(es, cursor);
754		lastRet = cursor;
755	<	if (--cursor < 0) cursor = elements.length - 1;
755	>	cursor = dec(cursor, es.length);
756		remaining--;
757		return e;
758		}
759
760		void postDelete(boolean leftShifted) {
761		if (!leftShifted)
762	<	if (++cursor >= elements.length) cursor = 0;
762	>	cursor = inc(cursor, elements.length);
763		}
764
765		public final void forEachRemaining(Consumer<? super E> action) {
766	<	final int k;
767	<	if ((k = remaining) > 0) {
768	<	remaining = 0;
769	<	forEachRemainingDescending(action, elements, cursor, k);
770	<	if ((lastRet = cursor - (k - 1)) < 0)
771	<	lastRet += elements.length;
766	>	Objects.requireNonNull(action);
767	>	int r;
768	>	if ((r = remaining) <= 0)
769	>	return;
770	>	remaining = 0;
771	>	final Object[] es = elements;
772	>	if (es[cursor] == null || sub(cursor, head, es.length) + 1 != r)
773	>	throw new ConcurrentModificationException();
774	>	for (int i = cursor, end = head, to = (i >= end) ? end : 0;
775	>	; i = es.length - 1, to = end) {
776	>	for (; i >= to; i--)
777	>	action.accept(elementAt(es, i));
778	>	if (to == end) {
779	>	if (end != head)
780	>	throw new ConcurrentModificationException();
781	>	lastRet = head;
782	>	break;
783	>	}
784		}
785		}
786		}
#	Line 785 | Line 799 | public class ArrayDeque<E> extends Abstr
799		* @since 1.8
800		*/
801		public Spliterator<E> spliterator() {
802	<	return new ArrayDequeSpliterator();
802	>	return new DeqSpliterator();
803		}
804
805	<	final class ArrayDequeSpliterator implements Spliterator<E> {
806	<	private int cursor;
807	<	private int remaining; // -1 until late-binding first use
805	>	final class DeqSpliterator implements Spliterator<E> {
806	>	private int fence;      // -1 until first use
807	>	private int cursor;     // current index, modified on traverse/split
808
809		/** Constructs late-binding spliterator over all elements. */
810	<	ArrayDequeSpliterator() {
811	<	this.remaining = -1;
810	>	DeqSpliterator() {
811	>	this.fence = -1;
812		}
813
814	<	/** Constructs spliterator over the given slice. */
815	<	ArrayDequeSpliterator(int cursor, int count) {
816	<	this.cursor = cursor;
817	<	this.remaining = count;
814	>	/** Constructs spliterator over the given range. */
815	>	DeqSpliterator(int origin, int fence) {
816	>	this.cursor = origin;
817	>	this.fence = fence;
818		}
819
820	<	/** Ensures late-binding initialization; then returns remaining. */
821	<	private int remaining() {
822	<	if (remaining < 0) {
820	>	/** Ensures late-binding initialization; then returns fence. */
821	>	private int getFence() { // force initialization
822	>	int t;
823	>	if ((t = fence) < 0) {
824	>	t = fence = tail;
825		cursor = head;
810	–	remaining = size;
826		}
827	<	return remaining;
827	>	return t;
828		}
829
830	<	public ArrayDequeSpliterator trySplit() {
831	<	final int mid;
832	<	if ((mid = remaining() >> 1) > 0) {
833	<	int oldCursor = cursor;
834	<	cursor = add(cursor, mid, elements.length);
835	<	remaining -= mid;
821	<	return new ArrayDequeSpliterator(oldCursor, mid);
822	<	}
823	<	return null;
830	>	public DeqSpliterator trySplit() {
831	>	final Object[] es = elements;
832	>	final int i, n;
833	>	return ((n = sub(getFence(), i = cursor, es.length) >> 1) <= 0)
834	>	? null
835	>	: new DeqSpliterator(i, cursor = add(i, n, es.length));
836		}
837
838		public void forEachRemaining(Consumer<? super E> action) {
839	<	final int k = remaining(); // side effect!
840	<	remaining = 0;
841	<	ArrayDeque.forEachRemaining(action, elements, cursor, k);
839	>	if (action == null)
840	>	throw new NullPointerException();
841	>	final int end = getFence(), cursor = this.cursor;
842	>	final Object[] es = elements;
843	>	if (cursor != end) {
844	>	this.cursor = end;
845	>	// null check at both ends of range is sufficient
846	>	if (es[cursor] == null || es[dec(end, es.length)] == null)
847	>	throw new ConcurrentModificationException();
848	>	for (int i = cursor, to = (i <= end) ? end : es.length;
849	>	; i = 0, to = end) {
850	>	for (; i < to; i++)
851	>	action.accept(elementAt(es, i));
852	>	if (to == end) break;
853	>	}
854	>	}
855		}
856
857		public boolean tryAdvance(Consumer<? super E> action) {
858	<	Objects.requireNonNull(action);
859	<	final int k;
860	<	if ((k = remaining()) <= 0)
858	>	if (action == null)
859	>	throw new NullPointerException();
860	>	int t, i;
861	>	if ((t = fence) < 0) t = getFence();
862	>	if (t == (i = cursor))
863		return false;
864	<	action.accept(nonNullElementAt(elements, cursor));
865	<	if (++cursor >= elements.length) cursor = 0;
866	<	remaining = k - 1;
864	>	final Object[] es;
865	>	action.accept(nonNullElementAt(es = elements, i));
866	>	cursor = inc(i, es.length);
867		return true;
868		}
869
870		public long estimateSize() {
871	<	return remaining();
871	>	return sub(getFence(), cursor, elements.length);
872		}
873
874		public int characteristics() {
#	Line 852 | Line 879 | public class ArrayDeque<E> extends Abstr
879		}
880		}
881
855	–	@SuppressWarnings("unchecked")
882		public void forEach(Consumer<? super E> action) {
883		Objects.requireNonNull(action);
884	<	final Object[] elements = this.elements;
885	<	final int capacity = elements.length;
886	<	int i, end, to, todo;
861	<	todo = (end = (i = head) + size)
862	<	- (to = (capacity - end >= 0) ? end : capacity);
863	<	for (;; to = todo, i = 0, todo = 0) {
884	>	final Object[] es = elements;
885	>	for (int i = head, end = tail, to = (i <= end) ? end : es.length;
886	>	; i = 0, to = end) {
887		for (; i < to; i++)
888	<	action.accept((E) elements[i]);
889	<	if (todo == 0) break;
888	>	action.accept(elementAt(es, i));
889	>	if (to == end) {
890	>	if (end != tail) throw new ConcurrentModificationException();
891	>	break;
892	>	}
893		}
894		// checkInvariants();
895		}
896
897		/**
872	–	* Calls action on remaining elements, starting at index i and
873	–	* traversing in ascending order.  A variant of forEach that also
874	–	* checks for concurrent modification, for use in iterators.
875	–	*/
876	–	static <E> void forEachRemaining(
877	–	Consumer<? super E> action, Object[] elements, int i, int remaining) {
878	–	Objects.requireNonNull(action);
879	–	final int capacity = elements.length;
880	–	int end, to, todo;
881	–	todo = (end = i + remaining)
882	–	- (to = (capacity - end >= 0) ? end : capacity);
883	–	for (;; to = todo, i = 0, todo = 0) {
884	–	for (; i < to; i++)
885	–	action.accept(nonNullElementAt(elements, i));
886	–	if (todo == 0) break;
887	–	}
888	–	}
889	–
890	–	static <E> void forEachRemainingDescending(
891	–	Consumer<? super E> action, Object[] elements, int i, int remaining) {
892	–	Objects.requireNonNull(action);
893	–	final int capacity = elements.length;
894	–	int end, to, todo;
895	–	todo = (to = ((end = i - remaining) >= -1) ? end : -1) - end;
896	–	for (;; to = (i = capacity - 1) - todo, todo = 0) {
897	–	for (; i > to; i--)
898	–	action.accept(nonNullElementAt(elements, i));
899	–	if (todo == 0) break;
900	–	}
901	–	}
902	–
903	–	/**
898		* Replaces each element of this deque with the result of applying the
899		* operator to that element, as specified by {@link List#replaceAll}.
900		*
#	Line 909 | Line 903 | public class ArrayDeque<E> extends Abstr
903		*/
904		/* public */ void replaceAll(UnaryOperator<E> operator) {
905		Objects.requireNonNull(operator);
906	<	final Object[] elements = this.elements;
907	<	final int capacity = elements.length;
908	<	int i, end, to, todo;
915	<	todo = (end = (i = head) + size)
916	<	- (to = (capacity - end >= 0) ? end : capacity);
917	<	for (;; to = todo, i = 0, todo = 0) {
906	>	final Object[] es = elements;
907	>	for (int i = head, end = tail, to = (i <= end) ? end : es.length;
908	>	; i = 0, to = end) {
909		for (; i < to; i++)
910	<	elements[i] = operator.apply(elementAt(i));
911	<	if (todo == 0) break;
910	>	es[i] = operator.apply(elementAt(es, i));
911	>	if (to == end) {
912	>	if (end != tail) throw new ConcurrentModificationException();
913	>	break;
914	>	}
915		}
916		// checkInvariants();
917		}
#	Line 949 | Line 943 | public class ArrayDeque<E> extends Abstr
943		/** Implementation of bulk remove methods. */
944		private boolean bulkRemove(Predicate<? super E> filter) {
945		// checkInvariants();
946	<	final Object[] elements = this.elements;
947	<	final int capacity = elements.length;
948	<	int i = head, j = i, remaining = size, deleted = 0;
946	>	final Object[] es = elements;
947	>	// Optimize for initial run of survivors
948	>	for (int i = head, end = tail, to = (i <= end) ? end : es.length;
949	>	; i = 0, to = end) {
950	>	for (; i < to; i++)
951	>	if (filter.test(elementAt(es, i)))
952	>	return bulkRemoveModified(filter, i, to);
953	>	if (to == end) {
954	>	if (end != tail) throw new ConcurrentModificationException();
955	>	break;
956	>	}
957	>	}
958	>	return false;
959	>	}
960	>
961	>	/**
962	>	* Helper for bulkRemove, in case of at least one deletion.
963	>	* @param i valid index of first element to be deleted
964	>	*/
965	>	private boolean bulkRemoveModified(
966	>	Predicate<? super E> filter, int i, int to) {
967	>	final Object[] es = elements;
968	>	final int capacity = es.length;
969	>	// a two-finger algorithm, with hare i reading, tortoise j writing
970	>	int j = i++;
971	>	final int end = tail;
972		try {
973	<	for (; remaining > 0; remaining--) {
974	<	@SuppressWarnings("unchecked") E e = (E) elements[i];
975	<	if (filter.test(e))
976	<	deleted++;
977	<	else {
978	<	if (j != i)
979	<	elements[j] = e;
980	<	if (++j >= capacity) j = 0;
973	>	for (;; j = 0) {    // j rejoins i on second leg
974	>	E e;
975	>	// In this loop, i and j are on the same leg, with i > j
976	>	for (; i < to; i++)
977	>	if (!filter.test(e = elementAt(es, i)))
978	>	es[j++] = e;
979	>	if (to == end) break;
980	>	// In this loop, j is on the first leg, i on the second
981	>	for (i = 0, to = end; i < to && j < capacity; i++)
982	>	if (!filter.test(e = elementAt(es, i)))
983	>	es[j++] = e;
984	>	if (i >= to) {
985	>	if (j == capacity) j = 0; // "corner" case
986	>	break;
987		}
965	–	if (++i >= capacity) i = 0;
988		}
989	<	return deleted > 0;
989	>	return true;
990		} catch (Throwable ex) {
991	<	if (deleted > 0)
992	<	for (; remaining > 0; remaining--) {
993	<	elements[j] = elements[i];
972	<	if (++i >= capacity) i = 0;
973	<	if (++j >= capacity) j = 0;
974	<	}
991	>	// copy remaining elements
992	>	for (; i != end; i = inc(i, capacity), j = inc(j, capacity))
993	>	es[j] = es[i];
994		throw ex;
995		} finally {
996	<	size -= deleted;
997	<	clearSlice(elements, j, deleted);
996	>	if (end != tail) throw new ConcurrentModificationException();
997	>	circularClear(es, tail = j, end);
998		// checkInvariants();
999		}
1000		}
#	Line 990 | Line 1009 | public class ArrayDeque<E> extends Abstr
1009		*/
1010		public boolean contains(Object o) {
1011		if (o != null) {
1012	<	final Object[] elements = this.elements;
1013	<	final int capacity = elements.length;
1014	<	int i, end, to, todo;
996	<	todo = (end = (i = head) + size)
997	<	- (to = (capacity - end >= 0) ? end : capacity);
998	<	for (;; to = todo, i = 0, todo = 0) {
1012	>	final Object[] es = elements;
1013	>	for (int i = head, end = tail, to = (i <= end) ? end : es.length;
1014	>	; i = 0, to = end) {
1015		for (; i < to; i++)
1016	<	if (o.equals(elements[i]))
1016	>	if (o.equals(es[i]))
1017		return true;
1018	<	if (todo == 0) break;
1018	>	if (to == end) break;
1019		}
1020		}
1021		return false;
#	Line 1027 | Line 1043 | public class ArrayDeque<E> extends Abstr
1043		* The deque will be empty after this call returns.
1044		*/
1045		public void clear() {
1046	<	clearSlice(elements, head, size);
1047	<	size = head = 0;
1046	>	circularClear(elements, head, tail);
1047	>	head = tail = 0;
1048		// checkInvariants();
1049		}
1050
1051		/**
1052	<	* Nulls out count elements, starting at array index from.
1052	>	* Nulls out slots starting at array index i, upto index end.
1053		*/
1054	<	private static void clearSlice(Object[] elements, int from, int count) {
1055	<	final int capacity = elements.length, end = from + count;
1056	<	final int leg = (capacity - end >= 0) ? end : capacity;
1057	<	Arrays.fill(elements, from, leg, null);
1058	<	if (leg != end)
1059	<	Arrays.fill(elements, 0, end - capacity, null);
1054	>	private static void circularClear(Object[] es, int i, int end) {
1055	>	for (int to = (i <= end) ? end : es.length;
1056	>	; i = 0, to = end) {
1057	>	Arrays.fill(es, i, to, null);
1058	>	if (to == end) break;
1059	>	}
1060		}
1061
1062		/**
#	Line 1061 | Line 1077 | public class ArrayDeque<E> extends Abstr
1077		}
1078
1079		private <T> T[] toArray(Class<T[]> klazz) {
1080	<	final Object[] elements = this.elements;
1065	<	final int capacity = elements.length;
1066	<	final int head = this.head, end = head + size;
1080	>	final Object[] es = elements;
1081		final T[] a;
1082	<	if (end >= 0) {
1083	<	a = Arrays.copyOfRange(elements, head, end, klazz);
1082	>	final int size = size(), head = this.head, end;
1083	>	final int len = Math.min(size, es.length - head);
1084	>	if ((end = head + size) >= 0) {
1085	>	a = Arrays.copyOfRange(es, head, end, klazz);
1086		} else {
1087		// integer overflow!
1088	<	a = Arrays.copyOfRange(elements, 0, size, klazz);
1089	<	System.arraycopy(elements, head, a, 0, capacity - head);
1088	>	a = Arrays.copyOfRange(es, 0, size, klazz);
1089	>	System.arraycopy(es, head, a, 0, len);
1090		}
1091	<	if (end - capacity > 0)
1092	<	System.arraycopy(elements, 0, a, capacity - head, end - capacity);
1091	>	if (tail < head)
1092	>	System.arraycopy(es, 0, a, len, tail);
1093		return a;
1094		}
1095
#	Line 1115 | Line 1131 | public class ArrayDeque<E> extends Abstr
1131		*/
1132		@SuppressWarnings("unchecked")
1133		public <T> T[] toArray(T[] a) {
1134	<	final int size = this.size;
1135	<	if (size > a.length)
1134	>	final int size;
1135	>	if ((size = size()) > a.length)
1136		return toArray((Class<T[]>) a.getClass());
1137	<	final Object[] elements = this.elements;
1138	<	final int capacity = elements.length;
1139	<	final int head = this.head, end = head + size;
1140	<	final int front = (capacity - end >= 0) ? size : capacity - head;
1141	<	System.arraycopy(elements, head, a, 0, front);
1142	<	if (front != size)
1127	<	System.arraycopy(elements, 0, a, capacity - head, end - capacity);
1137	>	final Object[] es = elements;
1138	>	for (int i = head, j = 0, len = Math.min(size, es.length - i);
1139	>	; i = 0, len = tail) {
1140	>	System.arraycopy(es, i, a, j, len);
1141	>	if ((j += len) == size) break;
1142	>	}
1143		if (size < a.length)
1144		a[size] = null;
1145		return a;
#	Line 1164 | Line 1179 | public class ArrayDeque<E> extends Abstr
1179		s.defaultWriteObject();
1180
1181		// Write out size
1182	<	s.writeInt(size);
1182	>	s.writeInt(size());
1183
1184		// Write out elements in order.
1185	<	final Object[] elements = this.elements;
1186	<	final int capacity = elements.length;
1187	<	int i, end, to, todo;
1173	<	todo = (end = (i = head) + size)
1174	<	- (to = (capacity - end >= 0) ? end : capacity);
1175	<	for (;; to = todo, i = 0, todo = 0) {
1185	>	final Object[] es = elements;
1186	>	for (int i = head, end = tail, to = (i <= end) ? end : es.length;
1187	>	; i = 0, to = end) {
1188		for (; i < to; i++)
1189	<	s.writeObject(elements[i]);
1190	<	if (todo == 0) break;
1189	>	s.writeObject(es[i]);
1190	>	if (to == end) break;
1191		}
1192		}
1193
#	Line 1191 | Line 1203 | public class ArrayDeque<E> extends Abstr
1203		s.defaultReadObject();
1204
1205		// Read in size and allocate array
1206	<	elements = new Object[size = s.readInt()];
1206	>	int size = s.readInt();
1207	>	elements = new Object[size + 1];
1208	>	this.tail = size;
1209
1210		// Read in all elements in the proper order.
1211		for (int i = 0; i < size; i++)
#	Line 1202 | Line 1216 | public class ArrayDeque<E> extends Abstr
1216		void checkInvariants() {
1217		try {
1218		int capacity = elements.length;
1219	<	// assert size >= 0 && size <= capacity;
1220	<	// assert head >= 0;
1221	<	// assert capacity == 0 || head < capacity;
1222	<	// assert size == 0 || elements[head] != null;
1223	<	// assert size == 0 || elements[tail()] != null;
1224	<	// assert size == capacity || elements[dec(head, capacity)] == null;
1225	<	// assert size == capacity || elements[inc(tail(), capacity)] == null;
1219	>	// assert head >= 0 && head < capacity;
1220	>	// assert tail >= 0 && tail < capacity;
1221	>	// assert capacity > 0;
1222	>	// assert size() < capacity;
1223	>	// assert head == tail || elements[head] != null;
1224	>	// assert elements[tail] == null;
1225	>	// assert head == tail || elements[dec(tail, capacity)] != null;
1226		} catch (Throwable t) {
1227	<	System.err.printf("head=%d size=%d capacity=%d%n",
1228	<	head, size, elements.length);
1227	>	System.err.printf("head=%d tail=%d capacity=%d%n",
1228	>	head, tail, elements.length);
1229		System.err.printf("elements=%s%n",
1230		Arrays.toString(elements));
1231		throw t;

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